In general, in the prevailing vehicle door latch device used hitherto, when a lock mechanism is in a locked state, a door is not opened by a door opening operation of an open handle. However, in the door latch device added with the one-motion door opening mechanism, even when the lock mechanism is in the locked state, a return to an unlocked state of the lock mechanism and an opening of the door are almost simultaneously performed by the door opening operation of an inside open handle.
The one-motion mechanism is a very convenient mechanism. However, since the one-motion mechanism makes it possible to release the locked state and open the door by the operation of the inside open handle, it is generally adopted only to the door latch device of the driver's door.
The one-motion mechanism is a mechanism closely related to another mechanism of the door latch device, and is designed with another mechanism at the same time. Hence, it has been practically impossible to add the one-motion door opening mechanism to the door latch device having no one-motion mechanisms at a later time.
Because of the described reason above, heretofore, the door for other than the driver's seat has been unable to enjoy the convenience of the one-motion door opening mechanism.